In view of the unique composition of hair fibers and the numerous changes that occur in styles and fashion, both the waving of hair and the dyeing of hair have long been of particular interest. In particular, hair color alteration by dyeing while permanent waving hair for long-lasting style retention have long been sought by many individuals. However, due to the composition of hair fiber, either the color or curls are not retained as long as desired and the simultaneous permanent waving and dyeing of hair fibers has not been realized in a broadly useable product.
In order to best understand the reasons for the inability of the hair fiber to retain curls for substantially long time periods or to be simultaneously permanently waved and colored, it is important to understand that hair is composed of a unique protein material called "keratin" and which is distinguished by the fact that it contains a very significant amount of an amino acid (cystine) which contains the element sulfur in addition to the elements nitrogen, oxygen, carbon and hydrogen. In the natural synthesis of hair, the element sulfur covalently links intra or inter polypeptide chains (K) through two sulfur atoms (S--S) to give keratin protein (K--S--S--K). Only by chemical action can this covalent linkage be broken.
In this regard, many prior art compositions have been developed for the "cold permanent waving" of hair. Typically, these prior art systems treat the hair with a reducing agent which breaks the disulfide (cystine) linkage in the hair. This chemical process typically follows after the hair is wound around a curling rod.
In general, permanent hair waving is usually carried out by subjecting the hair to reagents containing a free--thiol group e.g.,--SH. These materials are also called mercaptans. In this treatment, the hair usually is either wrapped on the rods with water or the lotion containing the thiol, and then saturated with thiol lotion. The thiol waving agent acts to break the disulfide bonds within the hair fiber forming thiol groups in the hair protein and disulfide bonds between two thiol waving agent molecules. The chemistry involved in the reaction of the mercaptan with the cystine disulfide bonds in the hair fiber is illustrated by the following chemical equations: EQU KSSK+2RSH.revreaction.2KSH+RSSR EQU KSSK+RSH.revreaction.KSSR+KSH
When a sufficient number of hair disulfide bonds have been broken, the hair is realigned to pair previously unpaired hair protein thiol groups opposite each other. At this point, the hair is rinsed, removing the unreacted thiol waving agent and any water soluble disulfide reaction products formed from it. Then, the hair is saturated with an oxidizing agent, or neutralizer, such as hydrogen peroxide or bromate salt, to reform disulfide bonds between the newly paired hair protein thiols, thereby giving the hair a new configuration or wave, or adding curl to the hair. By rebonding the sites of the reduced keratin in their new curled configuration, a permanent set which is impervious to water is established.
Much of the rebonding of the reduced sites is accomplished by the action of the chemical oxidizing agent, typically hydrogen peroxide, and can be illustrated by the following chemical reaction: EQU 2 KSH+H.sub.2 O.sub.2 .fwdarw.KSSK+2H.sub.2 O
One problem typically found in the prior art occurs when an individual wishes to dye hair which had been permanently waved. In these circumstances, the dye uptake will usually be uneven from the root to the tip of the hair fibers due to the structural alteration caused to the hair fiber by the permanent wave process. In practice, this problem is often circumvented by waiting for the hair to "heal", by allowing for a substantial time interval in which aerial oxidation reseals the excessively damaged areas, thereby providing hair fibers which are more amenable to dye uptake in a level manner.
Consumers have long sought to have a composition and process which would enable both color and permanent waving to be achieved simultaneously. However, no prior art system has been able to provide an effective or reliable composition which would enable simultaneous coloring and permanent waving of hair fibers. In fact, even though this need has existed in the art for decades, no successful commercial product has been attained which satisfies the consumer's need.
Prior to the advance detailed in U.S. Pat. No. 5,094,662, no prior art system existed for effectively permanently waving and permanently dyeing hair simultaneously. In the procedure detailed in this prior art patent, the dye must be incorporated in the permanent waving lotion to provide the permanent dyeing of the hair.
Although the teaching of U.S. Pat. No. 5,094,662 is highly effective in producing results previously unattainable, there is no teaching or suggestion in U.S. Pat. No. 5,094,662 which achieves a long lasting, durable semi-permanent dyeing or coloring for hair wherein the dye is mixed with the neutralizer. It is this area which the present invention has overcome.
The principal concern that has existed in the prior art is that the typical processes used to color hair involve contacting the hair with a mixture of dyes and ammonia and hydrogen peroxide. This combination can cause irreversible damage to the keratin matrix of the hair fiber. Furthermore, in order to be effective, the process requires some mode of swelling of the hair to allow for the penetration of the dye. In the case of tint impartation, whereby the deposited color is a shade or tone lighter than the naturally underlying color, a bleaching of the natural color is required.
Due to the attention that has been given to hair dyeing, the mechanisms involved in the action of dye formation are well understood. In addition, the damage done to the hair fibers is also well-known. In particular, some characteristics of this damage are the dimmunization of the structural integrity of the hair fibers, as evidenced by the loss of resiliency and increased porosity or capability to uptake water.
One principal factor which has led prior art investigators to seek achieving adequate hair dyeing and permanent waving concurrently is the belief that one can capitalize on the increased swelling of the hair which occurs during the reduction step of the permanent wave process. By contacting the hair with a dyestuff composition at this time, greater dye penetration is achieved, as compared to the dye uptake during the typical process of applying hair dyes in a separate process. In addition, by adding the dyestuff to the neutralizing mixture, it is believed that the dyes enter the hair more freely while the hair fibers are in the reduced state.
In spite of the possibility of increased damage to the hair fibers due to the combination of a perming lotion with an oxidative dyestuff composition, the expected longevity of the dyes in hair and the retention of the imparted color were important factors in pursuing this method. The following patents are representative of the prior art technology that has been developed.
In European Patent Application 0260,716A and U.S. Pat. No. 5,161,553, the use of oxidative dyestuffs is disclosed for being applied to hair in the mixture of a neutralizing composition following a permanent wave process. In this teaching, the hair is contacted with a permanent wave lotion while wrapped about a molding rod, rinsed thoroughly and then saturated with a neutralizing composition, typically between 2.2% and 3% hydrogen peroxide. After approximately one-half the time required for neutralizing, the hair is again contacted with the neutralizing composition, but this time a suitable amount of dyestuffs has been added to the composition so as to impart color during the final phase of the process.
Another prior art teaching of using permanent dyestuffs during the neutralizing step is found in U.S. Pat. No. 4,630,621. In this patent, a broad teaching of dyestuffs is claimed to be useful. However, the examples found in the patent focus principally on the use of oxidation dyes. The sole illustration of a direct dye merely employs a derivative of an anthraquinone, which is typically included in permanent hair dyeing compositions only to achieve the blue tones.
Although this patent suggests that the addition of the dyestuffs to the neutralizer attains both an acceptable curl and dye uptake by the hair fibers in a uniform manner, we have found the actual results achieved by employing the processes of the patent are unacceptable. In our experiments, all of which are detailed below, each of the processes defined in the examples of U.S. Pat. No. 4,630,621 were repeated. In each instance, the resulting dyeing and permanent wave characteristics of the hair fibers were significantly weaker than the results attained when the dyestuffs are used without the permanent waving solution.
It is not clear why the process taught in U.S. Pat. No. 4,630,621 results in a minimal dye uptake. However, we believe that there are several explanations as to why the methods taught in this prior art reference fail to deliver acceptable results.
One underlying reason for the failure to obtain intensive coloring may be a result of the attempt to impart dyestuffs into the hair fiber in an acidic medium. The acid pH of the neutralizer composition causes a rapid decrease in hair swelling that could inhibit dye penetration. Consequently, the dyestuffs fail to enter the hair fibers and are removed during the final rinsing.
Another reason is that during permanent waving, the hair is wrapped about a forming rod under tension. The hair is then secured about this rod with an elastic band stretched across the hair bundle, which creates a pressure line where the band is contacting the hair.
Another problem in the prior art is that permanent wave compositions typically contain materials which effectively assist the permanent waving lotion in wetting the hair. For example, proteinaceous quaternary materials, such as are available commercially in the form of Finquat, manufactured by Stepan Chemical Co. of Northfield, Ill. and Maypon, manufactured by Finetex of Elmwood Park, N.J., give the benefit of a conditioned feel to the hair by coating the hair's surface.
Unfortunately, in the presence of such conditioning and wetting agents, the waving lotion inhibits the penetration of such lipophilic materials as coal tar derived dyes while in an aqueous medium, such as the peroxide derived neutralizing compositions commonly employed. The result is an area across at least one section of the hair which does not have an adequate amount of dye uptake. This causes a "banding" effect on the hair fibers, which is clearly undesirable, as it gives poor color results.
This "banding" phenomenon may have been anticipated in U.S. Pat. No. 4,630,621, since the preferred method suggests applying the dye containing solution after the waving lotion has been removed. By employing the suggested method, the majority of the wetting agents are rinsed off, prior to being able to impede the penetration of the dyestuff into the hair.
It is also apparent that other practitioners in this art discovered the phenomenon that conditioning agents affect the dyeing capability when performed concurrently with permanent waving. This realization is evident from the teaching in U.S. Pat. No. 3,368,941 and 3,399,682, wherein hair conditioning materials of the classification of a quaternary amine are shown to be useable with specific dyestuffs of certain classes. In U.S. Pat. No. 3,368,941, acid and metalized dyestuffs are used as pre-existing colored materials. These dyes are attracted to cationic chemicals such as those found in quaternary amine conditioners. While not specifically taught in this patent, hair dyed with this system has limited durability beyond several shampooings. In U.S. Pat. No. 3,399,682, the use of azo dyes is shown to deliver results similar to that of the preceding patent.
Therefore, it is a principal object of the present invention to provide a permanent waving composition and method of application which is capable of providing permanent waving and hair dyeing concurrently.
Another object of the present invention is to provide a permanent waving and hair dyeing composition and method of application having the characteristic features described above which is also capable of providing a long lasting durable semi-permanent coloring to the hair.
Another object of the present invention is to provide a permanent waving composition and process for application thereof having the characteristic features described above which is easy to employ and is capable of providing intense color uptake uniformly distributed along the entire length of the hair fiber.
Other and more specific objects will in part be obvious and will in part appear hereinafter.